Answer:
The frequency , speed and wavelength of an electromagnetic wave are related by the formula
Speed = frequency x wavelength
frequency = speed / wavelength
substituting the values
frequency = 3 x #10 ^8# m /s / 1 x #10^15# m
= 3 x #10^-7# /s
Answer:
4
Explanation:
All of them are significant figures
Answer:
a. Microwaves—3 and infrared waves—1
Explanation:
Microwaves and infrared waves are both part of the electromagnetic spectrum, but they have different frequency and wavelength.
In particular:
- Microwaves are long-wavelength electromagnetic waves, with wavelength between 1 mm and 1 m. Their wavelength is longer than visible light
- Infrared waves are also long-wavelength electromagnetic waves, but their wavelength is shorter than microwaves: between 700 nm and 1 mm. Their wavelength is also longer than visible light.
The two types of waves are also used for different purposes. In particular:
- Infrared waves are emitted by any hot object, and their intensity depends on the temperature of the object. Therefore, they are used in astronomy to show the heat released by astronomical objects (option 1)
- Microwaves are used to study the Cosmic Microwave Background (CMB). This is electromagnetic radiation that permeates the whole universe, and its wavelength depends inversely on the local temperature. Therefore, areas with longer wavelength have lower temperature, and viceversa. Therefore, microwaves are used to measure temperature differences in space (option 3).
Mass of the block = 1.4 kg
Weight of the block = mg = 1.4 × 9.8 = 13.72 N
Normal force from the surface (N) = 13.72 N
Acceleration = 1.25 m/s^2
Let the coefficient of kinetic friction be μ
Friction force = μN
F(net) = ma
μmg = ma
μg = a
μ = 
μ = 
μ = 0.1275
Hence, the coefficient of kinetic friction is: μ = 0.1275
